Ergonomically designed portable seat cushion

ABSTRACT

A portable cushion that minimizes the blocking of blood circulation, stress, and pain in the femoral region caused by sitting on a chair for long hours or an extended time is provided. The overall shape of the cushion resembles human lungs connected to each other at the upper part with an upper surface that is flat, except for two wing portions. The wings are in a convex shape. The cushion is made of EP (Ethylene-Propylene Copolymer) rubber foam. A straight shallow center groove is concavely developed on the upper surface of the cushion along the direction of the wings. Two concave grooves, resembling hemi-oval shapes being cut along the long center axis thereof are developed on the flat upper surface of the seat cushion to receive ischial tuberosities of a user. A shell-shaped concave groove for receiving the coccyx of the user is developed on the rear part of the flat upper surface of the cushion between the two hemi-oval shape grooves. The front side of the cushion, between the two wings, is caved in for receiving and positioning of genitals of the user. The unique geometry of the cushion reduces the pressure to the ischial tuberosities and the coccyx of a user by maximizing the contact area and distribute the user&#39;s weight throughout the surface, while minimizing the blocking of blood circulation by minimizing the contact area of the wings of the cushion and the rear part of the thighs of the user.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Current application relates to a portable elastic rubber cushion for providing a comfortable pose to a user who is sitting on a seat for an extended period.

2. Description of the Prior Art

U.S. Pat. No. 4,132,228 to Green illustrates a comfort support seat cushion assembly providing even pressure distribution on the gluteal region with pressure relief for the ischial tuberosities, coccyx, and perineum. The overall shape of the seat cushion is the bottom face of a common chair with a hole on the perineum-contacting portion. Whole surface is concavely carved.

U.S. Pat. No. 4,643,481 to Saloff, et al. illustrates a seat system comprised of a base and cushion for a wheel chair. The base has a specially contoured support surface including a forward section and a rearward section. The rearward section has a pair of wings surrounding a void over which the user's ischia and coccyx are to be positioned at the same time.

U.S. Pat. No. 4,718,727 to Sheppard illustrates a reversible seat supplement including upper and lower portions which are both contoured, generally concave on one side and convex on the other side; and a keyhole shaped opening including an enlarged opening toward the rear at the base of the spine and the coccyx, and a narrow slot for the anal and urogenital triangle region extending forward to a point more than half way across the seat. Wedge shaped openings angling forward and outward from the central portion of the seat avoid pressure on the sciatic nerves.

U.S. Pat. No. 4,824,174 to Dunn, Sr. illustrates a seat device including a spacing portion from the back portion to a point considerably short of the front rim. The spacing portion is shaped on a T with an enlargement section to accommodate the genital area of a seated person. The back portion is designed to alleviate stress and pain on the coccyx of the seated person, which is responsible for major backache symptoms. The enlargement area allows for circulation to the genitals and anus for proper ventilation of the genitals to avoid excessive perspiration in these areas.

U.S. Pat. No. 5,286,089 to Goldman illustrates a unitary foam seat cushion (10) that is configured and arranged to eliminate contact pressure on the rectal, perineal and genital regions of a person seated on the seat cushion without subjecting the perineal region to substantial stress or tension. The seat cushion includes a base (12) and two upwardly projecting elongate support members (16 and 18). The support members are of an arcuate (upwardly extending convex) cross-sectional geometry and are positioned in parallel spaced apart relationship for support of the ischia and thighs. Located between the support members is a channel (14) that extends downwardly into the seat cushion to form a void that prevents exertion of contact pressure on the rectal, perineal and genital areas. The portions (30 and 32) of the support members nearest the knees of a seated person taper downwardly for improved weight distribution and comfort of a person seated on the seat cushion.

U.S. Pat. No. 6,591,141 to Lee illustrates a mat for hot compress and acupressure equipped with a roller type hyperthermo-radiative apparatus facing minimum friction resistance upon horizontal movement thereof. The mat includes a mat member foldable at one side thereof and with a longitudinal groove formed in the center thereof. Curved rails are formed at both sides of the central groove on the bottom of the mat member, which has curved portions corresponding to the curvature of the vertebral region of a user. Also, a roller type hyperthermo-radiative apparatus that travels along the curved rails and a conveying mechanism for moving the roller type hyperthermo-radiative apparatus in a horizontal direction are included.

None of the prior art provides a seat cushion having a structure for minimizing blood pressure build up, stress and pain in the femoral region by minimizing contact area between the rear thighs and the cushion as shown in this application.

SUMMARY OF THE INVENTION

It is the purpose of this invention to provide a portable seat cushion that minimizes blocking of blood pressure circulation, stress and pain in the femoral region due to sitting on a seat for an extended period, such as long range driving and international flights in the economy section. The overall shape of the cushion resembles human lungs connected to each other at the upper part with an upper surface that is flat with the exception of two wing portions. The wings are in a convex shape. The cushion is made of EP (Ethylene-Propylene Copolymer) rubber foam. A straight shallow center groove is concavely developed on the upper surface of the cushion, dividing it into two geometrically identical shapes. Air can move through this groove to remove sweat and other organic vapors accumulated during the long periods of sitting on the same seat. Two concave grooves, resembling hemi-oval shapes being cut along the long center axis thereof are developed on the flat upper surface of the seat cushion to receive ischial tuberosities of a user. The two hemi-oval shape grooves are located symmetrically apart from the center groove and positioned on the middle of the flat upper surface of the cushion. A shell shape concave groove for receiving the coccyx of a user is developed on the flat upper surface of the cushion. The coccyx-receiving groove is located between the rear sides of the two hemi-oval shape grooves. Perimeters of the coccyx receiving groove and the two hemi-oval shape grooves are overlapped. The front side of the cushion, between the two wings, is caved in a bay shape for receiving and positioning the genitals of the user. This space allows free circulation of blood and heat radiation from the genitals of the user. The unique geometry of the cushion reduces the pressure to the ischial tuberosities and the coccyx of a user by maximizing the contact area while minimizing the blocking of blood circulation by minimizing the contact area of the wings of the cushion and the rear part of the thighs of the user.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the seat cushion of the current application.

FIG. 2 is an over view of the seat cushion of the current application.

FIG. 3 is a cross sectional view of the cushion along the line A-A′ of the FIG. 2.

FIG. 4 is a cross sectional view of the cushion along the line B-B′ of the FIG. 2.

FIG. 5 is a cross sectional view of the cushion along the line C-C′ of the FIG. 2.

FIG. 6 is a cross sectional view of the cushion along the line D-D′ of the FIG. 2.

FIG. 7 is a schematic overview showing the overlap of a user's lower body on the seat cushion of the current application.

FIG. 8 is a schematic front view showing the point of contact of the cushion and the rear part of the thigh of a user.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1 to FIG. 4, the overall shape of the seat cushion (1) resembles a human lungs connected to each other at the upper part with an upper surface (2) that is flat except two wing portions (3). The wing portions (3) are in a convex shape and the tip (4) is in round shape. The seat cushion (1) is made of EP (Ethylene-Propylene Copolymer) rubber foam.

A straight shallow center groove (5) is concavely developed on the upper surface of the cushion dividing it into two geometrically identical shapes. Air moves through this groove (5) to remove sweat and other organic vapors accumulated during the long period of time on the same seat. The center groove (5) is hemi-tube shape of 4.76 mm width by 2.38 mm depth.

Two concave grooves (6), resembling hemi-oval shape of being cut along the long center axis thereof, are developed on the flat upper surface (2) of the seat cushion (1) to receive ischial tuberosities of a user. The depth (7) of the ischial tuberosite receiving groove (6) is in the range of 18 mm to 30 mm depends on the size of the cushion (1). The length of the longer axis (8) of the ischial tuberosite-receiving groove (6) is 140 mm and the length of the shorter axis (9) is 120 mm. The two ischial tuberosite receiving grooves (6) are positioned with an angle (10) to the horizontal upper surface. The angle (10) between the horizon and the inner surface of the ischial tuberosite-receiving groove (6) that locates close to the center groove (5) is in the range of 25 to 30 degrees for men and 35 to 40 degrees for women. The two hemi-oval shape grooves (6) are located symmetrically apart from the center groove (5) and positioned on the middle of the flat upper surface (2) of the cushion (1). This geometry distributes the pressure of the weight of the user throughout the broad surface area of the hemi-oval shape grooves (6) to allow smooth circulation of the blood of the user in the lower part of the body.

A shell shaped concave groove (12) for receiving the coccyx of a user is developed on the flat upper surface of the cushion. The coccyx-receiving groove (12) is located between the rear sides of the two hemi-oval shape grooves (6). Perimeters of the coccyx receiving groove (12) and the two hemi-oval shape grooves (6) are overlapped. The depth of the shell shape groove (12) is in the range of 5 mm to 8 mm. The shell shape concave groove (12) resembles the shape of the coccyx of a human body to maximize the contact area between the coccyx of the user and the seat cushion to reduce the pressure and pain caused by the body weight.

The front side of the cushion (13), between the two wing portions (3), is caved in for receiving and positioning of genitals of the user. Depth (14) of the cave (15) is 40 mm to 45 mm. That free space of the cave (15) allows free blood circulation in the genitals of the user and removes heat radiated from the genitals by the air to maintain the genitals in healthy condition.

FIG. 5 is a cross sectional view of the seat cushion (1) along the line C-C′ of the FIG. 2. Cross sectional line C-C′ is not a straight line. It is a step line to show the relative position of the ischial tuberositie-receiving groove (6) along direction of the central groove (5). The ischial tuberositie-receiving groove (6) is developed between the front of the flat upper surface and the half of the rear part of the flat upper surface (2).

FIG. 6 is a cross sectional view of the cushion along the line D-D′, along the center groove (5), of the FIG. 2 to show the relative position of the shell shape groove (12). It shows that the shall shape groove (12) is located just behind the horizontal center of the flat upper surface (2).

FIG. 7 is a schematic over view showing the overlap of a user's lower body (16) on the seat cushion (1) of the current application. Two ischia bones (17) of the user are located on the ischial tuberosite receiving grooves (6) and coccyx bone (19) is positioned on the coccyx-receiving groove (12). Then the two legs (20) of the user are positioned over the wing portions (3) along their length. FIG. 8 is a schematic front view showing the contacting point of the seat cushion (1) and the rear part (21) of the thigh (22) of a user. The rear part (21) of the user's thighs (22) contact with the convex wing portions (3) of the seat cushion (1). The minimum contact along the rear part of the user's thigh (22) minimizes blocking of the circulation of the blood in the legs because all the main vascular tracts in the human's leg are laid along the length of the leg. In all of the prior arts, the user's legs are surrounded by the seat cushion and press all the vascular tracts throughout the whole length of the thighs. 

1. A seat cushion resembling a human lungs connected to each other at the upper part with an upper surface that is flat except two wing portions, which are in a convex shape with round shape tips, made of EP (Ethylene-Propylene Copolymer) rubber foam.
 2. A seat cushion of claim 1, wherein 1) a straight shallow center groove of hemi-tube shape with 4.76 mm width by 2.38 mm depth is concavely developed on the upper surface of the cushion dividing the cushion into two geometrically identical shapes, 2) two concave ischial tuberosities receiving grooves located symmetrically apart from the center groove and positioned on the middle of the flat upper surface of the cushion with an angle to the center groove, resembling hemi-oval shape of being cut along the long center axis thereof to have length of the longer axis 140 mm and the length of the shorter axis 120 mm, and having depth in the range of 18 mm to 30 mm depends on the size of the cushion, are developed on the flat upper surface of the seat cushion, 3) a shell shaped concave groove having depth in the range of 5 mm to 8 mm for receiving the coccyx of a user is located between the rear sides of the two hemi-oval shape grooves for receiving ischial tuberosities of a user developed on the flat upper surface of the cushion, 4) a front side, between the two wing portions, is caved in with a radius of 45 mm for receiving and positioning of genitals of the user to allow free blood circulation, and 5) two convex wings portions are developed to contact with the rear part of the thighs of the of a user along the length of the leg.
 3. A seat cushion of claim 1, wherein the angle between the horizon surface and the inner surface of the ischial tuberosite-receiving groove that locates close to the center groove is in the range of 25 to 30 degrees for men and 35 to 40 degrees for women. 